1. Field of the Invention
The invention relates generally to rear mirrors for motor vehicles and more particularly to rear mirrors for use by persons other than the driver of a vehicle.
2. Discussion of the Prior Art
Vehicles having restricted fields of view, such as trucks, recreational vehicles or other vehicles pulling trailers, rely on external rear view mirrors to enhance the field of view of the person driving the vehicle. A driver's attention while driving a vehicle is typically directed toward the front of the vehicle. While driving in a right lane, a driver may observe from the left-hand driver's seat the left lane behind the vehicle by casting a quick glance into, for example, the left-hand outside mirror of the vehicle. If the vehicle has a restricted field of view toward the rear, a right-hand outside rear view mirror is typically required to afford the driver a view toward the right of the vehicle, as would be needed for a lane change toward the right.
To observe traffic conditions on the left rear side of the vehicle, a driver sitting in the left driver's seat of a vehicle only needs to turn his or her head through a relatively small angle away from the forward viewing direction. On the other hand, to look into a rear view mirror on the right side of the vehicle, for example, to quickly ascertain whether a lane change to the right is permissible, a driver's view needs to be turned through a considerable angle toward the right and away from the forward direction of the vehicle. Thus, the left rear of a truck, for example, may be observed while typically still viewing the forward direction with peripheral vision. On the other hand, looking toward the right rear of a truck requires, that almost all of a driver's attention is directed away from the main direction of travel.
The right-hand rear of a truck, consequently, holds greater dangers that a vehicle may inadvertently be overlooked and that an accident may happen. It is also realized that the danger of a driver missing the presence of a vehicle on the right-hand side may be greater when the driver is inexperienced than when a driver has already gained many hours of experience in driving view-obstructed vehicles. For example, it is not unusual for transportation companies to provide driver trainers for newly employed drivers. The driver trainers provide instruction to the new drivers and seek to reduce the risk of accidents during the time the newly hired driver becomes acquainted with the equipment. Because of the increased risk factors involved in steering a vehicle toward the side opposite the driver's side, it is desirable to allow the trainer or, more generally, the person sitting next to the driver to keep the side and rear opposite to the driver's side in view during maneuvers of the vehicle to that critical side. These maneuvers include not only lane changes but understandably also turns of the vehicle to that side.